From 4e0f33ffe018b07021f627328f0a207550d1b374 Mon Sep 17 00:00:00 2001 From: Arne Jansen Date: Fri, 11 Sep 2015 09:18:56 -0700 Subject: [PATCH] Illumos 6214 - zpools going south 6214 zpools going south Reviewed by: Igor Kozhukhov Reviewed by: George Wilson Reviewed by: Dan McDonald Reviewed by: Saso Kiselkov References: https://www.illumos.org/issues/6214 http://cr.illumos.org/~webrev/sensille/6214_zpools_going_south/ Porting Notes: Reintroduce b_compress to the l2arc_buf_hdr_t. In commit b9541d6 the compression flags were moved to the generic b_flags in the arc_buf_hdr_t. This is a problem because l2arc_compress_buf() may manipulate the compression flags and this can only be done safely under the hash lock which is not held. See Illumos 6214 for a detailed analysis of the race. HDR_GET_COMPRESS() macro was removed from arc_buf_info(). Ported-by: Brian Behlendorf Closes #3757 --- include/sys/arc.h | 14 -------------- include/sys/arc_impl.h | 1 + module/zfs/arc.c | 35 +++++++++++++++-------------------- 3 files changed, 16 insertions(+), 34 deletions(-) diff --git a/include/sys/arc.h b/include/sys/arc.h index f88fe0298..db7a64aa2 100644 --- a/include/sys/arc.h +++ b/include/sys/arc.h @@ -105,20 +105,6 @@ typedef enum arc_flags /* Flags specifying whether optional hdr struct fields are defined */ ARC_FLAG_HAS_L1HDR = 1 << 17, ARC_FLAG_HAS_L2HDR = 1 << 18, - - /* - * The arc buffer's compression mode is stored in the top 7 bits of the - * flags field, so these dummy flags are included so that MDB can - * interpret the enum properly. - */ - ARC_FLAG_COMPRESS_0 = 1 << 24, - ARC_FLAG_COMPRESS_1 = 1 << 25, - ARC_FLAG_COMPRESS_2 = 1 << 26, - ARC_FLAG_COMPRESS_3 = 1 << 27, - ARC_FLAG_COMPRESS_4 = 1 << 28, - ARC_FLAG_COMPRESS_5 = 1 << 29, - ARC_FLAG_COMPRESS_6 = 1 << 30 - } arc_flags_t; struct arc_buf { diff --git a/include/sys/arc_impl.h b/include/sys/arc_impl.h index 5f9f49252..a9dbfc8dd 100644 --- a/include/sys/arc_impl.h +++ b/include/sys/arc_impl.h @@ -187,6 +187,7 @@ typedef struct l2arc_buf_hdr { /* real alloc'd buffer size depending on b_compress applied */ uint32_t b_hits; int32_t b_asize; + uint8_t b_compress; list_node_t b_l2node; } l2arc_buf_hdr_t; diff --git a/module/zfs/arc.c b/module/zfs/arc.c index 00d989028..7cd4e76f2 100644 --- a/module/zfs/arc.c +++ b/module/zfs/arc.c @@ -677,15 +677,6 @@ static arc_buf_hdr_t arc_eviction_hdr; #define HDR_HAS_L1HDR(hdr) ((hdr)->b_flags & ARC_FLAG_HAS_L1HDR) #define HDR_HAS_L2HDR(hdr) ((hdr)->b_flags & ARC_FLAG_HAS_L2HDR) -/* For storing compression mode in b_flags */ -#define HDR_COMPRESS_OFFSET 24 -#define HDR_COMPRESS_NBITS 7 - -#define HDR_GET_COMPRESS(hdr) ((enum zio_compress)BF32_GET(hdr->b_flags, \ - HDR_COMPRESS_OFFSET, HDR_COMPRESS_NBITS)) -#define HDR_SET_COMPRESS(hdr, cmp) BF32_SET(hdr->b_flags, \ - HDR_COMPRESS_OFFSET, HDR_COMPRESS_NBITS, (cmp)) - /* * Other sizes */ @@ -1483,7 +1474,7 @@ arc_buf_info(arc_buf_t *ab, arc_buf_info_t *abi, int state_index) if (l2hdr) { abi->abi_l2arc_dattr = l2hdr->b_daddr; abi->abi_l2arc_asize = l2hdr->b_asize; - abi->abi_l2arc_compress = HDR_GET_COMPRESS(hdr); + abi->abi_l2arc_compress = l2hdr->b_compress; abi->abi_l2arc_hits = l2hdr->b_hits; } @@ -1954,7 +1945,7 @@ arc_buf_l2_cdata_free(arc_buf_hdr_t *hdr) * separately compressed buffer, so there's nothing to free (it * points to the same buffer as the arc_buf_t's b_data field). */ - if (HDR_GET_COMPRESS(hdr) == ZIO_COMPRESS_OFF) { + if (hdr->b_l2hdr.b_compress == ZIO_COMPRESS_OFF) { hdr->b_l1hdr.b_tmp_cdata = NULL; return; } @@ -1963,12 +1954,12 @@ arc_buf_l2_cdata_free(arc_buf_hdr_t *hdr) * There's nothing to free since the buffer was all zero's and * compressed to a zero length buffer. */ - if (HDR_GET_COMPRESS(hdr) == ZIO_COMPRESS_EMPTY) { + if (hdr->b_l2hdr.b_compress == ZIO_COMPRESS_EMPTY) { ASSERT3P(hdr->b_l1hdr.b_tmp_cdata, ==, NULL); return; } - ASSERT(L2ARC_IS_VALID_COMPRESS(HDR_GET_COMPRESS(hdr))); + ASSERT(L2ARC_IS_VALID_COMPRESS(hdr->b_l2hdr.b_compress)); arc_buf_free_on_write(hdr->b_l1hdr.b_tmp_cdata, hdr->b_size, zio_data_buf_free); @@ -4429,7 +4420,7 @@ top: (vd = hdr->b_l2hdr.b_dev->l2ad_vdev) != NULL) { devw = hdr->b_l2hdr.b_dev->l2ad_writing; addr = hdr->b_l2hdr.b_daddr; - b_compress = HDR_GET_COMPRESS(hdr); + b_compress = hdr->b_l2hdr.b_compress; b_asize = hdr->b_l2hdr.b_asize; /* * Lock out device removal. @@ -6037,6 +6028,8 @@ l2arc_read_done(zio_t *zio) if (cb->l2rcb_compress != ZIO_COMPRESS_OFF) l2arc_decompress_zio(zio, hdr, cb->l2rcb_compress); ASSERT(zio->io_data != NULL); + ASSERT3U(zio->io_size, ==, hdr->b_size); + ASSERT3U(BP_GET_LSIZE(&cb->l2rcb_bp), ==, hdr->b_size); /* * Check this survived the L2ARC journey. @@ -6073,7 +6066,7 @@ l2arc_read_done(zio_t *zio) ASSERT(!pio || pio->io_child_type == ZIO_CHILD_LOGICAL); zio_nowait(zio_read(pio, cb->l2rcb_spa, &cb->l2rcb_bp, - buf->b_data, zio->io_size, arc_read_done, buf, + buf->b_data, hdr->b_size, arc_read_done, buf, zio->io_priority, cb->l2rcb_flags, &cb->l2rcb_zb)); } } @@ -6381,7 +6374,7 @@ l2arc_write_buffers(spa_t *spa, l2arc_dev_t *dev, uint64_t target_sz, * can't access without holding the ARC list locks * (which we want to avoid during compression/writing) */ - HDR_SET_COMPRESS(hdr, ZIO_COMPRESS_OFF); + hdr->b_l2hdr.b_compress = ZIO_COMPRESS_OFF; hdr->b_l2hdr.b_asize = hdr->b_size; hdr->b_l2hdr.b_hits = 0; hdr->b_l1hdr.b_tmp_cdata = hdr->b_l1hdr.b_buf->b_data; @@ -6587,7 +6580,7 @@ l2arc_compress_buf(arc_buf_hdr_t *hdr) l2hdr = &hdr->b_l2hdr; ASSERT(HDR_HAS_L1HDR(hdr)); - ASSERT(HDR_GET_COMPRESS(hdr) == ZIO_COMPRESS_OFF); + ASSERT3U(l2hdr->b_compress, ==, ZIO_COMPRESS_OFF); ASSERT(hdr->b_l1hdr.b_tmp_cdata != NULL); len = l2hdr->b_asize; @@ -6605,7 +6598,7 @@ l2arc_compress_buf(arc_buf_hdr_t *hdr) if (csize == 0) { /* zero block, indicate that there's nothing to write */ zio_data_buf_free(cdata, len); - HDR_SET_COMPRESS(hdr, ZIO_COMPRESS_EMPTY); + l2hdr->b_compress = ZIO_COMPRESS_EMPTY; l2hdr->b_asize = 0; hdr->b_l1hdr.b_tmp_cdata = NULL; ARCSTAT_BUMP(arcstat_l2_compress_zeros); @@ -6615,7 +6608,7 @@ l2arc_compress_buf(arc_buf_hdr_t *hdr) * Compression succeeded, we'll keep the cdata around for * writing and release it afterwards. */ - HDR_SET_COMPRESS(hdr, ZIO_COMPRESS_LZ4); + l2hdr->b_compress = ZIO_COMPRESS_LZ4; l2hdr->b_asize = csize; hdr->b_l1hdr.b_tmp_cdata = cdata; ARCSTAT_BUMP(arcstat_l2_compress_successes); @@ -6702,9 +6695,11 @@ l2arc_decompress_zio(zio_t *zio, arc_buf_hdr_t *hdr, enum zio_compress c) static void l2arc_release_cdata_buf(arc_buf_hdr_t *hdr) { - enum zio_compress comp = HDR_GET_COMPRESS(hdr); + enum zio_compress comp; ASSERT(HDR_HAS_L1HDR(hdr)); + ASSERT(HDR_HAS_L2HDR(hdr)); + comp = hdr->b_l2hdr.b_compress; ASSERT(comp == ZIO_COMPRESS_OFF || L2ARC_IS_VALID_COMPRESS(comp)); if (comp == ZIO_COMPRESS_OFF) {